Re: [PATCH v2 03/10] DMA, CMA: separate core cma management codes from DMA APIs

[Minchan Kim <minchan@kernel.org>]

On Thu, Jun 12, 2014 at 12:21:40PM +0900, Joonsoo Kim wrote:
> To prepare future generalization work on cma area management code,
> we need to separate core cma management codes from DMA APIs.
> We will extend these core functions to cover requirements of
> ppc kvm's cma area management functionality in following patches.
> This separation helps us not to touch DMA APIs while extending
> core functions.
> 
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> 
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index fb0cdce..8a44c82 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -231,9 +231,9 @@ core_initcall(cma_init_reserved_areas);
>   * If @fixed is true, reserve contiguous area at exactly @base.  If false,
>   * reserve in range from @base to @limit.
>   */
> -int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> -				       phys_addr_t limit, struct cma **res_cma,
> -				       bool fixed)
> +static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> +				phys_addr_t base, phys_addr_t limit,
> +				struct cma **res_cma, bool fixed)
>  {
>  	struct cma *cma = &cma_areas[cma_area_count];
>  	phys_addr_t alignment;
> @@ -288,16 +288,30 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>  
>  	pr_info("%s(): reserved %ld MiB at %08lx\n",
>  		__func__, (unsigned long)size / SZ_1M, (unsigned long)base);
> -
> -	/* Architecture specific contiguous memory fixup. */
> -	dma_contiguous_early_fixup(base, size);
>  	return 0;
> +
>  err:
>  	pr_err("%s(): failed to reserve %ld MiB\n",
>  		__func__, (unsigned long)size / SZ_1M);
>  	return ret;
>  }
>  
> +int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> +				       phys_addr_t limit, struct cma **res_cma,
> +				       bool fixed)
> +{
> +	int ret;
> +
> +	ret = __dma_contiguous_reserve_area(size, base, limit, res_cma, fixed);
> +	if (ret)
> +		return ret;
> +
> +	/* Architecture specific contiguous memory fixup. */
> +	dma_contiguous_early_fixup(base, size);

In old, base and size are aligned with alignment and passed into arch fixup
but your patch is changing it.
I didn't look at what kinds of side effect it makes but just want to confirm.

> +
> +	return 0;
> +}
> +
>  static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>  {
>  	mutex_lock(&cma->lock);
> @@ -316,20 +330,16 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>   * global one. Requires architecture specific dev_get_cma_area() helper
>   * function.
>   */
> -struct page *dma_alloc_from_contiguous(struct device *dev, int count,
> +static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>  				       unsigned int align)
>  {
>  	unsigned long mask, pfn, pageno, start = 0;
> -	struct cma *cma = dev_get_cma_area(dev);
>  	struct page *page = NULL;
>  	int ret;
>  
>  	if (!cma || !cma->count)
>  		return NULL;
>  
> -	if (align > CONFIG_CMA_ALIGNMENT)
> -		align = CONFIG_CMA_ALIGNMENT;
> -
>  	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
>  		 count, align);
>  
> @@ -377,6 +387,17 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>  	return page;
>  }
>  

Please move the description in __dma_alloc_from_contiguous to here exported API.

> +struct page *dma_alloc_from_contiguous(struct device *dev, int count,
> +				       unsigned int align)
> +{
> +	struct cma *cma = dev_get_cma_area(dev);
> +
> +	if (align > CONFIG_CMA_ALIGNMENT)
> +		align = CONFIG_CMA_ALIGNMENT;
> +
> +	return __dma_alloc_from_contiguous(cma, count, align);
> +}
> +
>  /**
>   * dma_release_from_contiguous() - release allocated pages
>   * @dev:   Pointer to device for which the pages were allocated.
> @@ -387,10 +408,9 @@ struct page *dma_alloc_from_contiguous(struct device *dev, int count,
>   * It returns false when provided pages do not belong to contiguous area and
>   * true otherwise.
>   */
> -bool dma_release_from_contiguous(struct device *dev, struct page *pages,
> +static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
>  				 int count)
>  {
> -	struct cma *cma = dev_get_cma_area(dev);
>  	unsigned long pfn;
>  
>  	if (!cma || !pages)
> @@ -410,3 +430,11 @@ bool dma_release_from_contiguous(struct device *dev, struct page *pages,
>  
>  	return true;
>  }
> +

Ditto.

> +bool dma_release_from_contiguous(struct device *dev, struct page *pages,
> +				 int count)
> +{
> +	struct cma *cma = dev_get_cma_area(dev);
> +
> +	return __dma_release_from_contiguous(cma, pages, count);
> +}
> -- 
> 1.7.9.5

-- 
Kind regards,
Minchan Kim